docstr: Return the file extension of the written files.
docstr_tok: ["Return","the","file","extension","of","the","written","files","."]
code: def extension(self):
      """Return the file extension of the written files."""
      return ATDSWriter._AVRORECORD_EXTENSION
  
imports: import os
  import hashlib
  import json
  import numpy
  import tensorflow
  from avro.schema import Parse
  from avro.datafile import DataFileWriter
  from avro.io import DatumWriter
  from tests.test_atds_avro.utils.file_writer import FileWriter
  from tests.test_atds_avro.utils.generator.varlen_tensor_generator import VarLenTensorGeneratorBase
  from tensorflow_io.python.experimental.atds.features import DenseFeature, SparseFeature, VarlenFeature
label_desc: Use image node_id 2 for calling the ATDSWriter obj's underlying member method code with example usage: obj.extension() and returns: ATDSWriter